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8th Grade L1 Vocab
Science Explorer Book L Ch 1 Vocabulary
| Term | Definition |
|---|---|
| element | a substance that cannot be broken down into any other substance by chemical or physical means |
| compound | a substance made of two or more elements chemically combined in a specific ratio, or proportion |
| mixture | two or more substances that are mixed together but not chemically combined |
| energy level | the specific amount of energy an electron has valence electrons |
| atomic number | the number of protons in the nucleus of an atom |
| period | elements in the same horizontal row of the periodic table |
| group | elements in the same vertical column of the periodic table; also called a family |
| family | elements in the same vertical column of the periodic table; also called a group |
| noble gas | an element from group 18 in the periodic table of elements |
| ionic bond | the attraction between oppositely charged ions |
| polyatomic ion | an ion that is made of more than one atom |
| covalent bond | a chemical bond formed when two atoms share electrons |
| molecule | a neutral particle made of two or more atoms joined by covalent bonds |
| polar bond | a covalent bonding which electrons are shared unequally |
| metallic bond | an attraction between a positive metal ion and the electrons surrounding it |
| valence electrons | the electrons that are in the highest energy level of an atom and that are involved in chemical reactions |